Session Time: 5:30pm-7:30pm
Presentation Time: 5:30pm-7:30pm
Location: Hall C & D
*Purpose: Vascular composite allotransplantation (VCA) transplantation is a life-transforming procedure with encouraging results. Despite the recent advances, the immunological response in these patients is still not fully understood. Innate Lymphoid Cells (ILCs) are innate cells with a lymphoid origin. ILCs has emerged as important players in several inflammatory disorders. ILCs are classified based on an analogy to T helper (Th) cells subsets regarding the expression of transcription effectors, cytokine production and function. ILC1, ILC2 and ILC3 mirror Th1, Th2 and Th17 cells, respectively. In humans, ILC3 can be divided in NKp44– or NKp44+ cells. The role of ILC subsets in VCA transplantation has never been assessed.
*Methods: Immunephenotyping of ILCs was performed in PBMCs and skin biopsies (after digestion with collagenase) by flow cytometry. Skin biopsies were also analyzed by immunofluorescence. Since 2011, we collected specimens from VCA recipients (6 full facial and 3 limb transplants) prospectively in our center: pre-tx, 24h, 1-week and months 3,6,12,24,36 post-tx as well as when rejection was clinically suspected. ILCs were defined as Lineage-CD127+.
*Results: We identified that majority of IL-17 produced by circulating or tissue-resident cells were not coming from T cells (CD3–), underlying a potential inflammatory role for ILCs following transplantation (p<0.05). ILC numbers were decreased after induction therapy in the peripheral blood (p<0.05). However, the proportion of ILC2 (p<0.05) and ILC3 NKp44+ (p<0.01) expanded over time. Also, skin-homing marker CLA was increased in circulating ILC1 over time (p<0.05). Rejections were characterized by an increase in ILC3 NKp44+ cells in the skin allograft (p<0.05) and a reduction in the blood (p<0.001). When we analyzed infiltrating skin allograft cells, we found that the phenotype of ILCs were different in facial compared to limb recipients, with greater ILC1 in the former and ILC3 in the latter. Interestingly, circulating total ILCs increased in face (p<0.05), and a decreased in limb recipients (p<0.05) during rejection, suggesting differences in the local immune response.
*Conclusions: Our initial observational data suggest a potential role for ILCs in VCA transplantation with dominant IL-17 production by ILC3 during face rejection and greater ILC1 in limb rejections.
To cite this abstract in AMA style:Borges TJ, O’Malley JT, Kollar B, Pomahac B, Talbot SG, Riella LV. Characterization of Innate Lymphoid Cells in Full Facial and Limb Transplant Recipients [abstract]. Am J Transplant. 2019; 19 (suppl 3). https://atcmeetingabstracts.com/abstract/characterization-of-innate-lymphoid-cells-in-full-facial-and-limb-transplant-recipients/. Accessed March 4, 2021.
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